JPH0669314B2 - Inverter device for electric compressor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an inverter device for controlling the drive of an electric compressor for compressing a refrigerant such as an air conditioner, and more particularly to an inverter device for driving an electric compressor. The present invention relates to an inverter device for an electric compressor capable of reducing vibration.

[Prior Art] FIG. 3 is a block circuit diagram showing a conventional inverter device for an electric compressor shown in Japanese Utility Model Laid-Open No. 61-202200.

In the figure, (1) is a power supply consisting of alternating current of a constant frequency and voltage supplied from a normal distribution system, (2) is a diode rectifier that converts alternating current into direct current, (3) is a capacitor for voltage doubler, (4) ) Is a smoothing capacitor that smoothes the rectified direct current, and (5) an inverter that is a power conversion device that converts the rectified direct current into an alternating current of a predetermined frequency and voltage,
(6) is an electric compressor for compressing a refrigerant such as an air conditioner,
(7) is a drive unit for directly driving the inverter (5),
(8) is a microcomputer that controls the output voltage and output frequency of the inverter (5) via the drive unit (7), (9) is a casing that forms the outer shell of the electric compressor (6), ) Is a vibration sensor attached to the housing (9).

The conventional inverter device for an electric compressor is configured as described above, and the electric compressor (6) is constituted by the inverter (5).
Is controlled appropriately. However, various vibrations are generated along with the driving of the electric compressor (6). Therefore,
In this type of inverter device for an electric compressor, efforts are being made to reduce such vibrations.

The vibration suppressing operation by the conventional inverter device for an electric compressor will be described below.

The electric power applied from the power supply (1) through the diode rectifier (2) is converted into alternating current again by the inverter (5) and applied to the electric compressor (6). The output frequency and the output voltage of the inverter (5) at this time are a frequency pattern determined by the microcomputer (8) according to the air conditioning conditions (hereinafter, referred to as V / F pattern).
The PWM signal according to the above is output to the inverter (5) for control.

At this time, a signal from a vibration sensor (10) attached to the housing (9) of the electric compressor (6) is also input to the microcomputer (8). Vibration of the casing (9) is detected from this signal, and the electric compressor (6) is operated at an output frequency that avoids the current operating frequency. Thereby, the vibration of the housing (9) is reduced.

There is also an example in which the output voltage is lowered to operate as shown in JP-A-62-118790.

[Problems to be Solved by the Invention] In the conventional inverter device for an electric compressor as described above,
The vibration was reduced by operating the electric compressor (6) at an output frequency different from the frequency of the housing (9).

However, depending on the relationship between the output frequency of the inverter (5) and the vibration cycle of the housing (9), the vibration between the electric compressor (6) and the housing (9) may increase in a predetermined cycle, or Noise was sometimes generated. Further, when the electric compressor (6) is operated at an output frequency that avoids the operating frequency that resonates, the operation that continuously changes the operating frequency cannot be performed. Further, although there is a means for operating by reducing the output voltage, in this case, the vibration is not always suppressed.

Then, this invention makes it a subject to provide the inverter apparatus for electric compressors which can change an operating frequency continuously and can reduce the vibration of an electric compressor more reliably.

[Means for Solving the Problem] In the inverter device for an electric compressor according to the present invention, when the detection value by the vibration frequency detecting means for detecting the vibration state during driving of the electric compressor (6) is a certain value or more, First inverter output control means for maintaining the current output frequency of the inverter (5) and changing the output voltage to suppress the detection value by the frequency detection means to a certain value or less; and the first inverter output. When the value detected by the frequency detecting means cannot be reduced to a certain value or less by changing the output voltage by the control means, the output frequency of the inverter (5) is changed to reduce the detected value of the frequency detecting means to a certain value or less. And a second inverter output control means for suppressing.

[Operation] In the inverter device for an electric compressor of the present invention, the first inverter output control is performed when the value detected by the frequency detecting means for detecting the vibration state of the electric compressor (6) during driving is equal to or more than a certain value. By means of the means, the current output frequency of the inverter (5) is maintained, and the output voltage is changed to suppress the detection value by the frequency detection means to a certain value or less. However, when the value detected by the frequency detecting means cannot be reduced to a certain value or less by changing the output voltage, the second inverter output control means changes the output frequency of the inverter (5) to detect the frequency by the frequency detecting means. Since the value is suppressed below a certain value, when the vibration of the electric compressor (6) is large,
First, the vibration of the electric compressor (6) is suppressed below a predetermined level by the first inverter output control means, and the vibration of the electric compressor (6) falls below a predetermined level by the first inverter output control means. Even if it cannot be suppressed, the vibration of the electric compressor (6) can be suppressed below a predetermined level by the second inverter output control means.

[Embodiment] FIG. 1 is a block circuit diagram showing an inverter device for an electric compressor according to an embodiment of the present invention. In the figure, (1)
Since the items (9) to (9) are the same as or correspond to the components of the above-described conventional example, the duplicate description will be omitted here.

In the figure, (11) is an acceleration sensor for detecting the frequency of the electric compressor (6), and (12) is a detection circuit for inputting the signal of the acceleration sensor (11) to the microcomputer (8). . The acceleration sensor (11) and the detection circuit (12) constitute a vibration frequency detection means for detecting the vibration state of the electric compressor (6) during driving.

The inverter device for the electric compressor of this embodiment is configured as described above, and controls the output of the inverter (5) according to the signal from the frequency detecting means to generate the electric compressor (6).
Suppresses the vibration of. The operating principle itself for appropriately controlling the driving of the electric compressor (6) by the inverter (5) is the same as the conventional one. Therefore, here, the vibration suppressing operation of the electric compressor (6) by the inverter device for the electric compressor will be described.

In this embodiment, the vibration of the electric compressor (6) detected by the acceleration sensor (11) is transmitted as a detection signal to the microcomputer (8) via the detection circuit (12). When this detection signal is equal to or greater than a certain value, the vibration suppressing operation by the microcomputer (8) is started.

FIG. 2 is a flowchart showing the vibration suppressing operation of the electric compressor by the microcomputer of the inverter device for the electric compressor shown in FIG. The operation of the inverter device for the electric compressor will be described below with reference to FIG.

First, in step S1, a reference value is set in order to use the current output voltage and frequency as a reference. In step S2, it is judged whether or not the detection signal by the vibration frequency detecting means for detecting the vibration state of the electric compressor (6) during driving is equal to or more than a certain value. If it is less than a certain value, the operation is continued with the V / F pattern currently set in step S10. That is, the output voltage and the output frequency of the inverter 5 are maintained in the same output state as the present. However, if the detection signal is above a certain value, the output voltage of the inverter (5) is changed in step S3 to increase the voltage. In step S4, the detection signal is detected again, and it is determined whether the detection signal has become larger than that before the change. When the detection signal becomes small, the current V / F pattern is maintained in step S10. On the contrary, when it becomes large in step S4, the process proceeds to step S5, and the output voltage is reduced. In step S6, the detection signal is judged again, and if it becomes smaller, the process proceeds to step S10 and the current V / F is maintained.

If it does not decrease in step S6, the operating frequency is changed. First, the output frequency is lowered in step S7, the detection signal is judged in step S8, and if it becomes smaller, step S1
Return and change the voltage again. If the detection signal becomes large, the frequency is increased in step S9 and the process returns to step S1.
Change the voltage.

As described above, in the inverter device for the electric compressor of this embodiment, when the value detected by the vibration frequency detecting means for detecting the vibration state of the electric compressor (6) during driving is equal to or more than a certain value, first, the second The first inverter output control means shown in step S1 to step S6 of the inverter (5)
The current output frequency is maintained, the output voltage is changed, and the detection value by the frequency detection means is suppressed to a certain value or less. When the value detected by the frequency detecting means cannot be reduced to a certain value or less due to the change of the output voltage, the output of the inverter (5) is output by the second inverter output control means shown in steps S7 and S9 of FIG. By changing the frequency, the value detected by the frequency detecting means is suppressed to a certain value or less.

That is, in this embodiment, when the vibration of the electric compressor (6) is large, first, the output voltage of the inverter (5) is changed to slightly change the rotation speed of the electric compressor (6) to reduce the vibration. Plan. Next, when the vibration cannot be reduced only by changing the voltage, the output frequency is changed to slightly change the rotation speed of the electric compressor (6) to reduce the vibration.

Therefore, when the vibration of the electric compressor (6) can be suppressed below a predetermined level by the first inverter output control means, the frequency can be continuously changed to operate the electric compressor (6). It enables quiet and smooth driving control. Even if the first inverter output control means cannot suppress the vibration of the electric compressor (6) to a predetermined level or less, the second inverter output control means causes the vibration of the electric compressor (6) to be a predetermined level or less. Therefore, vibration can be reliably reduced, and highly reliable vibration suppressing operation can be performed.

By the way, in the above-mentioned embodiment, the vibration of the electric compressor (6) is detected by the acceleration sensor (11), and the vibration of the electric compressor (6) is reduced by changing the output voltage or the output frequency of the inverter (5). The inverter device for the electric compressor has been described. However, the vibration of the electric compressor (6) is also suppressed by controlling the open / closed state by operating a solenoid valve or the like provided in the middle of the refrigerant pipe connected to the electric compressor (6). It is possible to do so.

[Effects of the Invention] As described above, the inverter device for an electric compressor according to the present invention has the first structure when the value detected by the vibration frequency detecting means for detecting the vibration state of the electric compressor during driving is equal to or higher than a certain value. The current output frequency of the inverter is maintained by the inverter output control means, the output voltage is changed, and the detection value by the frequency detection means is suppressed to a certain value or less. Then, when the detection value from the frequency detection means cannot be reduced to a certain value or less by changing the output voltage, the output frequency of the inverter is changed by the second inverter output control means, and the detection value by the frequency detection means is changed. Is suppressed below a certain value. That is, when the vibration of the electric compressor is large, first, the vibration of the electric compressor can be suppressed by the first inverter output control means,
In this case, the electric compressor can be operated by continuously changing the frequency, and quiet and smooth operation control can be performed. Further, when the first inverter output control means cannot suppress the vibration of the electric compressor to a predetermined level or lower, the second inverter output control means can suppress the vibration of the electric compressor to a predetermined level or lower. The vibration can be reliably reduced and a highly reliable vibration suppressing operation becomes possible.

[Brief description of drawings]

FIG. 1 is a block circuit diagram showing an inverter device for an electric compressor according to an embodiment of the present invention, and FIG. 2 shows a vibration suppressing operation of an electric compressor by a microcomputer of the inverter device for an electric compressor shown in FIG. FIG. 3 is a block circuit diagram showing a conventional inverter device for an electric compressor. In the figure, 5: Inverter 6: Electric compressor 8: Microcomputer 11: Acceleration sensor 12: Detection circuit. In the drawings, the same reference numerals and symbols indicate the same or corresponding parts.

Claims (1)

[Claims] 1. An inverter for controlling driving of an electric compressor by controlling an output frequency and an output voltage, a frequency detecting means for detecting vibration during driving of the electric compressor, and a frequency detecting means. When the detected value is above a certain value,
The first inverter output control means for maintaining the current output frequency of the inverter and changing the output voltage to suppress the detection value by the frequency detection means to a certain value or less; and the first inverter output control means. The second inverter output for changing the output frequency of the inverter to suppress the value detected by the frequency detecting means to be less than a certain value when the value detected by the frequency detecting means cannot be less than the certain value due to the change of the output voltage. An inverter device for an electric compressor, comprising: a control unit.